Image heating apparatus having a positioning portion that positions a heater holder in a longitudinal direction

Abstract

An image heating apparatus includes a frame having first and second side plates. A cylindrical film is provided between the side plates, and a heater contacts an inner surface of the film. A roller forms a nip in cooperation with the heater through the film, and an image, formed on a recording material, is heated by heat of the heater, while moving in the nip. A holder holds the heater, and is provided in an inside space of the film. With respect to a longitudinal direction, a length of the holder is greater than a distance between the side plates. In addition, a stay, formed of metal, reinforces the holder, and is provided in the inside space of the film. A length of the stay is greater than the distance between the side plates, and a position of the stay with respect to the longitudinal direction is determined by the holder.

We claim: 
     
       1. An image heating apparatus comprising:
 (A) a frame including:
 (a) a first side plate provided at one end portion; and 
 (b) a second side plate provided at another end portion with respect to a longitudinal direction of said image heating apparatus; 
 
 (B) a cylindrical film provided between said first side plate and said second side plate and having an inside space; 
 (C) a heater provided in the inside space of said film; 
 (D) a roller forming a nip portion in cooperation with the heater through said film for nipping and feeding a recording material, wherein an image, formed on the recording material, is heated by heat of said heater, while the recording material moves in the nip portion; 
 (E) a holder for holding said heater, said holder being provided in the inside space of said film, and, with respect to the longitudinal direction, a length of said holder is greater than a distance between said first side plate and said second side plate, said holder including a positioning portion contacting said first side plate and positioning said holder to said first side plate with respect to the longitudinal direction; and 
 (F) a stay for reinforcing said holder, said stay being formed of metal, provided in the inside space of said film, and having a length greater than the distance between said first side plate and said second side plate, wherein a position of said stay with respect to the longitudinal direction is determined by said holder. 
 
     
     
       2. The image heating apparatus according to  claim 1 , wherein said stay includes a recessed shaped groove, and said holder includes a projected shaped portion, engaged with said recessed shaped groove, for positioning said stay with respect to the longitudinal direction. 
     
     
       3. The image heating apparatus according to  claim 2 , wherein the projected shaped portion is provided at a portion, with respect to the longitudinal direction, closer to the first plate than the second plate. 
     
     
       4. The image heating apparatus according to  claim 1 , further comprising:
 (G) a first preventing member, contactable to one end surface of said film when said film moves toward said first side plate, said first preventing member preventing movement of said film in the longitudinal direction, and said first preventing member engaging with said first side plate; and 
 (H) a second preventing member, contactable to the other end surface of said film when said film moves toward said second side plate, said second preventing member preventing the movement of said film in the longitudinal direction, and said second preventing member engaging with said second side plate. 
 
     
     
       5. The image heating apparatus according to  claim 1 , wherein said heater includes a plate shaped substrate and a heat generating resistor formed on said substrate. 
     
     
       6. The image heating apparatus according to  claim 5 , wherein said substrate is made of a ceramic. 
     
     
       7. An image heating apparatus comprising:
 (A) a frame including:
 (a) a first side plate provided at one end portion; and 
 (b) a second side plate provided at another end portion with respect to a longitudinal direction of said image heating apparatus; 
 
 (B) a cylindrical film provided between said first side plate and said second side plate and having an inside space; 
 (C) a nip forming unit provided in the inside space of said film and contacting an inner surface of said film, said nip forming unit including:
 (a) a heater; 
 (b) a holder for holding said heater, said holder including a positioning portion contacting said first side plate and positioning said holder to said first side plate with respect to the longitudinal direction, wherein, with respect to the longitudinal direction, a length of said holder is greater than a distance between said first side plate and said second side plate; and 
 (c) a stay made of metal for reinforcing said holder, wherein, with respect to the longitudinal direction, a length of said stay is greater than the distance between said first side plate and said second side plate, and wherein a position of said stay with respect to the longitudinal direction is determined by said holder; and 
 
 (D) a roller forming a nip portion in cooperation with said nip forming unit through said film for nipping and feeding a recording material, wherein an image, formed on the recording material, is heated by heat of said heater, while the recording material moves in the nip portion. 
 
     
     
       8. The image heating apparatus according to  claim 7 , wherein said stay includes a recessed shaped groove, and said holder includes a projected shaped portion, engaged with said recessed shaped groove, for positioning said stay with respect to the longitudinal direction. 
     
     
       9. The image heating apparatus according to  claim 8 , wherein the projected shaped portion is provided at a portion, with respect to the longitudinal direction, closer to the first plate than the second plate. 
     
     
       10. The image heating apparatus according to  claim 7 , further comprising:
 (G) a first preventing member, contactable to one end surface of said film when said film moves toward said first side plate, said first preventing member preventing movement of said film in the longitudinal direction, and said first preventing member engaging with said first side plate; and 
 (H) a second preventing member, contactable to the other end surface of said film when said film moves toward said second side plate, said second preventing member preventing the movement of said film in the longitudinal direction, and said second preventing member engaging with said second side plate. 
 
     
     
       11. The image heating apparatus according to  claim 7 , wherein said heater includes a plate shaped substrate and a heat generating resistor formed on said substrate. 
     
     
       12. The image heating apparatus according to  claim 11 , wherein said substrate is made of a ceramic.